Refrigerated display case



v Oct. 22, 1957 Filed April 16, 1956 P. J. REUTER ET AL 2,810,267

\ REFRIGERATED DISPLAY CASE 2 Shee'tS -Sheet 1 PHILLIP J. REUTER v BY DQNALD'A'.VOORH|ES ATTORNEY IN V EN TORS Oct. 22, 1957 P. J. REUTER ETAL 2,810,267

I REFRIGERATED DISPLAY CASE Filed April 16, 1956 2 Shets-Sheet 2 INVENTORS' PHILLIP J. REUTER BY DONALD A,VOORH\ES WJM.

ATTORNEY United States Patefi o F REFRIGERATED DISPLAY CASE Phillip J. Renter, Trenton, N. 1., and Donald A. Voorhies, Morrisville, Pa., assignors to C. V. Hill & Company, Inc., Trenton, N. J., a corporation of New Jersey Application April 16, 1956, Serial No. 578,321

3 Claims. (Cl. 62--89.5)

This invention relates to self service refrigerated display cases of the type which have a display space that is open at the top for access to customers. The invention is directed particularly to novel arrangements of elements 1 for refrigerating and circulating air flowing through and about the display space.

Self service display cases present many difficult problems in refrigeration and air circulation and, in particular, it is diflicult to maintain adequate and uniform cooling of the products on display while preventing the formation of ice or snow on the products on display and avoiding undue or localized accumulations of ice and snow on the evaporator coils. Moreover, it has been difficult heretofore to provide a display case including the compressor, condenser, drip pan and other elements in such a self contained arrangement as to render the assembly operable under all conditions of use and yet eliminate drain pipes and other elements which prevent ready installation of the case in any location, and permit movement thereof from one position to another.

Prior self service display cases have also been constructed in such a way that articles stacked in the display space are arranged in stepped relation so as to partially overlap the articles in an adjacent stack. As a result, the removal of one article often results in the upsetting of a whole stack of articles, rendering it diflicult for a customer to select any particular article desired from the tumbled arrangement of articles in the display space.

In accordance with the present invention, those limitations and objections to constructions of the prior art are overcome and display cases provided which are self contained, continuously operable and yet serve to insure improved and more uniform cooling of the products on display. The construction further serves to control the accumulation of ice and frost on the evaporators so as to facilitate the defrosting thereof. Display cases embodying the present invention also may be constructed so that articles may be stacked one upon another without overlapping the articles of another stack and, as a re sult, any article may be inspected and removed readily without upsetting an adjacent stack of articles.

The principal object of the present invention is to insure improved refrigeration of articles in a self service display case.

A further object of the invention is to improve the circulation of air about and through the display space of a self service display case.

Another object of the invention is to effectively overcome localized and undue accumulation of ice and snow on the coils of evaporators used in self service refrigerated display cases.

Another object of the invention is to' provide a novel type of refrigerated display case which is self contained and capable of installation or movement to any desired location.

,Another object of the invention is to provide a self service refrigerated display case with means for support-,

tion the packages 52, shown in full lines in Fig. 2, may be PatentedQct. 22, 1957 2 v 1 i-ng the articles on display in a manner which facilitates inspection and removal thereof by customers.

These and other objects and features of the invention will appear from the following description thereof wherein reference is madeto the figures of the accompanying drawings.

In the drawings: a v

Fig. 1 is a perspective illustration a typical form of self service refrigerated display case having the lower front panel thereof raised to show the arrangement of compressors;

Fig. 2 is a vertical sectional view through the display case illustrated in Fig. 1;

Fig. 3 is a top plan view of the construction shown in Figs. 1 and 2 with parts broken away; and

Fig. 4 is a diagrammatic wiring diagram illustrating a typical form of control system which may be used'in accordance with the present invention.

In that form of'the invention chosen for purposes of illustration in the drawings the display case is provided with an insulated front wall 2 surmounted by a transparent section 4 formed of multiple glass panes 6. The rear wall 8 of the case is insulated and extends upward somewhat above the level of the front wall 2 andis provided with a forwardly extending head portion 10.

The bottom of the case is also insulated and is constructed in a stepped formation with a forward portion 12 and a vertical portion 14 which cooperate to form a lower exterior housing 16 for the motors, compressors,v

condensers and electrical control units. The housing 16 is accessible from the front of the case and is normally closed by a decorative front panel 18 pivotally mounted at 20. The rear portion 22 of the insulated bottom extends rearwardly from the lower end of the vertical portion 12 to the rear insulated wall 8 forming an interior well 24 in which two blowers 26 and a portion of the evaporator coils 28 and 30 are located.

The display space 32 of the case is closed about the front, bottom and rear by elements which serve as the inner surfaces of air circulating ducts. Thus, the front wall of the display space is formed of a conducting element 34 spaced from the front wall 2 of the case to form a warm air duct 36 which has an inlet opening 38 at its upper end extending substantially the full length of the case. Air is thus drawn off from the top of the display space through inlet opening 38 and flows downward through the warm air duct 36 to the adjacent inlet side of a refrigerating space 40 beneath the element 42 which forms the bottom of the display space. The refrigerating chamber preferably extends substantially the full length of the case and the evaporator coils 28 and 30 may pass back and forth lengthwise of the case so as to present an extended length thereof to the air flowing through the refrigerating chamber. If desired, the element 42 forming the bottom of the display space may be at least partially insulated to limit the transfer of heat therethrough and aid in maintaining uniformity of air temperature throughout the display space 28.

The rear of the display space is formed of an element 44 which is spaced from the insulated rear wall 8 of the case to form a cold air duct 46 through which refrigerated air from the refrigerating chamber 40 is circulated upward to forwardly directed air outlets 48 and 50 beneath the head portion 10 of the case so as to flow forward into and across the top of the warm air duct 36.

The elements 34, 42 and 44 which define the front, bottom and rear of the display space 32 are preferably positioned at right angles to each other with the front and rear elements 34 and 44 inclined forwardly and the bottom 42 horizontally inclined so as to constitute a bin which is tilted forwardly somewhat. With this construcarranged in stacked relation without overlapping. The stepped and partially overlapping arrangement of packages in display spaces having the vertical front wall and inclined bottom-support of prior art constructions is thereby avoided. The articles therefore can be readily inspected and removed from any stack in the case without danger of upsetting an adjacent stack and scattering the packages over top of eachother so that one item will conceal others underneath the resulting pile of mixed articles.

In order to refrigerate and circulate the. air for preserving the articles on display at the desired temperature, the case is preferably providedwith two independently operable motors, compressors, condensers and evaporators. For this purpose, one motor and compressorunit, indicated generally at 56, is located adjacent one end of the case within the housing 16 extendingalongthe lower front portion ofthe case, whereas a second motor and compressor unit 58, is locatedinthe housing 16 adjacent the opposite end of the case. Thecondenser 60 associated with the unit 56 is located in the central portion of the case within the housing 16, whereas the condenser 62 associated with the unit 58 is also located in the central portion of the housing 16, but positioned above the condenser 60. A drippan 64 for receiving water draining off the evaporators during the defrosting cycle is located beneath the condensers 60 and 62 within the housing 16 and each motor-compressor unit is provided with a fan 66 for drawing air inward through a front of the housing 16 and causing it to flow over the condensers and across the condensate collected in the drip pan 64. The condensate or drip water is thus warmed by the condensers and evaporated by the air flowing over the drip pan and is caused to flow over the motor-compressor unit to aidin cooling the unit prior to being discharged through the housing 16 near the end of the case. Both fans 66 are operated continuously even whenthe adjacent motor-compressor unit is idle so that evaporation of the drip water is assured under all conditions of operation.

Each motor-compressor unit serves to supply refrigerant to a different set of evaporator coils located in the refrigerating space 40. The coils of the evaporator associated with the motor-compressorunit 56 and condenser 60 are indicated at 28 and are positioned above and to the rear of the coils 30 associated with the motor-compressor unit 58 and condenser 62. Thus, air flowing through the refrigerating chamber 40 will be cooled by the evaporator coils 28 and 30 or either ofthem and in the event either unit should be turned off or fail for any reason, the coils of the other evaporator will serve to cool the air being circulated and maintain the displayspace at a safe low temperature at all times and until the idle compressor is again placed in service.

The electrical control means for the motor-compressor units are preferably located in the housing 16 between the condensers and the units, as shown generally at 68 and 70, and are arranged to insure continued operation of one unit even upon failure of the other. The refrigerating load of the active unit will, of course, increase when the other unit is inactive but the control means employed permit increase in such 'load sufficient to insure effective.

refrigeration of the air being circulated by either set of the evaporator coils 28 or 3t); The system thus will operate in a failure-proof mannerpreventing loss of refrigeration under even the most adverse conditions of opera tion.

The air refrigerated by the evaporators 28 and 30 is circulated by means of the blowers 26 located in the well 24 positioned at the rear of the front housing 16 and above the rear insulated portion 22 of the bottom of the case. The air is drawn inward through the upper inlet opening 38 of the warm air duct 36 fromthe top of the display space 32 along the front thereof, and flows downward to the inlet side of the refrigerating chamber 40 where, it is cooled by the evaporator coils 28 and 30 or either of them. The cooled, air then fiows through-the.

refrigerating chamber and downwardly in the rear portion thereof to an outlet beneath the lower edge of a baffle 72 to enter the bottom of the well 24 in which the blowers 26 are located.

A portion of the air forced upward through the well 24 by the blowers flows forward through an air distributing screen 74 and between the battle 76 and the bottom element 44 of the display space so as to issue in a jet-like stream from the port 78 near the foremost coils of the evaporators 68' and 70. The air issuing from port 78 mingles with the relatively warm air and opposes or retards its flow from the warm air duct 36 to the refrigerating chamber 40. The turbulence thus created in the air approaching the evaporator coils causes the air to be retarded and distributed substantially uniformly over the coils throughout the full length of the case. If such retarding and turbulence were not created the air would tend to be sucked toward the blowers 26 in paths bounded by the dotted lines 80 in Fig. 3, creating dead air spaces in the areas 82. However, by creating the turbulence and reducing the velocity of the air as it flows over the evaporator coils substantially the entire length of the coils may be effectively utilized and the deposition of moisture thereon is rendered more uniform. On the other hand, since the air issuing from port 78 has already been refrigerated, it causes rapid condensation of the moisture contained in the warm air and insures deposit of such moisture on the foremost coils of the evaporators 28 and 30. Thereafter, during the defrosting cycle of operation, the air being circulated flows over heating elements 84 and 86 located near the foremost coils so as to insure rapid defrosting of the evaporator while using relatively small and localized heating elements.

Recirculation of at least a portion of the refrigerated air over the evaporator coils and the retarded and turbulent flow of the air over substantially the entire area of the evaporator further serves to increase the cfiiciency of the evaporator and eliminate localized air flow. The temperature of the air may thus be reduced more effectively by at least partial recirculation permitting the use of smaller evaporator coils and efficient use thereof.

The major portion of the air forced upward from the Well 24 by the blowers 26 flows upward through the cold air duct 46 between the rear insulated wall 8 and the rear element 44 of the display space. Screen 88 located near the top of the cold air duct insures uniform distribution of the refrigerated air throughout the length of the case, whereas a second air screen 90 serves to divide the upwardly flowing air into two distinct air channels. The front air channel 92 terminates in a relatively large lower outlet 48 through which the cold air flows into the top of the display space at limited velocity and in a turbulent manner which serves to insure circulation thereof about and over the articles within the display space 32. The rear air channel 94 of the cold air duct communicated with the upper, relatively narrow, discharge outlet 50. The refrigerated air issues from the outlet 50 at relatively high speed so as to flow across the top of the display space in a jet and in a manner to form an air curtain preventing downward flow of warm air from above the display space into contact with the articles on display.

The air from both outlets 48 and 50, in flowing forward, returns to the air inlet opening 38 at the top of the warm air duct 36 and is thus returned to the refrigerating space 40 for recooling and recirculation.

The means employed for controlling operation of the motor-compressor units 56 and 58 preferably include thermostats 96 located in the display space 32, or elsewhere, to maintain the display space and the articles therein at a desired temperature. In addition, the circuits preferably include a time clock 98 which may be set to establish a predetermined defrosting period, say from 1 to 1:30 oclock in the morning. Upon operation of thentimeclocktheswitch 99 is opened to discontinue operation of the motor-compressor units while allowing the fans 66 to continue to operate. At the same time, the switch 100 is closed to energize the electric heating elements 84 and 86 adjacent the foremost coils of the evaporators 28 and 30. The blowers 26 continue to operate during the defrosting cycle so that air is circulated through and about the display space as before but the air approaching the evaporators is heated and serves to melt the ice and snow accumulated thereon. Moreover, since the cold air issuing from port 78 during the refrigerating cycle causes most of the moisture to condense on the foremost coils of the evaporator, the ice and snow will be caused to melt rapidly during the defrosting cycle. Extended heating elements, therefore, are

not required and the defrosting operation takes place rapidly.

The ice and frost which melts and drips from the evaporator coils drains down the rearwardly sloping upper surface of the forward portion 12 of the insulated bottom of the case to the well 24 from which it flows through a trap 104 to the drip pan 64 beneath the condensers 60 and 62 in the lower front housing 16. The condensate collects in the drip pan and is evaporated by the air which flows inward over the condensers and is warmed thereby before it flows over the water in the drip pan.

In the preferred operation of the equipment the case is provided with a defrost limit control means such as that shown and described in the patent to Smith No. 2,691,870. For this purpose a thermostatically operated switch 106 is located in the cold air duct 46, or elsewhere, and is responsive to an excessive rise in temperature to close switch 99 and open switch 100, so as to renew the refrigerating cycle and prevent dangerous overheating of the air in the display space.

The construction shown and described is thus operable to insure eflicient utilization of the evaporators and reduced temperature of the air being circulated. It also serves to accomplish the most effective refrigeration of articles in an open, self service, refrigerated display case and to afllord uniform cooling of the articles on display by reason of the dual streams of air circulating through and across the top of the display space. The dual motorcompressor units preclude failure of refrigeration, whereas the arrangement of the air ducts and bafiles aflt'ords the most eflicient utilization of the refrigerating and heating means during both the refrigerating and defrosting cycles.

The particular form and construction of the display case shown in the drawings and described above and the various elements thereof have been selected as typical of one embodiment of the invention. However, each of the elements may be changed in form, construction and arrangement in applying the invention to other types and styles of display cases. In view thereof, it should be understood that the embodiment of the invention particularly set forth and shown in the drawings is intended to be illustrative only and is not intended to limit the scope of the invention.

We claim:

1. A refrigerated display case having a display space which is open at the top for access to customers, a warm air duct having an inlet along one side of the display space, a cold air duct having an outlet along the opposite side of the display space near the top thereof, a refrigerating chamber having evaporator coils therein arranged in a series extending lengthwise of the case, said refrigerating chamber having an inlet side communicating with the warm air duct and an outlet side communicating with the cold air duct, a blower on the outlet side of the re frigerating chamber for circulating air through said chamher and ducts, and means for conducting a portion of the air leaving said chamber back to a point near the foremost coils of the series thereof in the refrigerating chamber, and heating means for defrosting said coils, located adjacent said foremost coils in the refrigerating chamber.

2. A refrigerated display case having a display space which is open at the top for access to customers, insulated front, bottom and rear walls extending about the display space and cooperating therewith to form air circulating ducts and a refrigerating chamber, a housing located adjacent the bottom of the display case at the front thereof and exterior to said insulated front and bottom, two separate motor-compressor units located in said housing and adjacent opposite ends of the case, condensers for said units located between said units and in said housing, a drip pan located beneath the condensers, blowers operable independently of said motor-compressor units for circulating air over said condensers and across said drip pan, evaporator coils connected to said units and located within said refrigerating chamber, means for defrosting said evaporator coils, and means for conducting water formed upon defrosting of said coils from the refrigerating chamber to said drip pan for evaporation thereof.

3. A refrigerated display case having a display space which is open at the top for access to customers, insulated front, bottom and rear walls extending about the display space and cooperating therewith to form a warm air duct having an inlet extending along the front of the display space, a cold air duct having an outlet extending along the rear of the rear of the display space near the top thereof, and a refrigerating chamber located beneath the display space and above the insulated bottom of the case, a blower located within the case for circulating air through said ducts, display space and refrigerating chamber, two sets of evaporator coils located in the refrigerating chamber, means for defrosting said coils, two independently operable motor-compressor units located exterior to said insulated walls of the case and having condensers located adjacent to each other and to a drip pan, a blower adjacent said condensers and operable to cause air to flow over the condensers to the drip pan, and means for conducting water from the refrigerating chamber to the drip pan during the defrosting cycle for evaporation thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,145,776 Muffly Ian. 31, 1939 2,474,480 MacMaster Jan. 10, 1950 2,630,684 Strang Mar. 10, 1953 2,635,434 Bently Apr. 21, 1953 2,669,851 Pichler Feb. 23, 1954 2,705,875 Pichler Apr. 12, 1955 2,762,205 Weber Sept. 11, 1956 

